The instant invention relates to an actuator of a safety switch for detecting and locking a specifiable state of an apparatus, in particular for detecting and locking the closed state of a safety device of a machine or the like, as well as a safety switch with an actuator of that type.
Safety switches are used, as an example, for monitoring the state of a safety device of a machine, for instance for monitoring the closed state of a protective door of a protective room for a machine tool or an industrial robot. The safety switch can provide an enabling signal for the operation of the machine in the closed state of the safety device. The safety switch provides a force-actuated interruption when the safety device is opened, for instance via an electrical contact pair that is to be actuated with a positive lock or via an electronic circuit element, an electrical circuit or multiple electrical circuits. The enabling signal is then no longer provided. The corresponding machine can then be put into a safe operating state, for instance shut down, or the machine can be prevented from being switched on.
It is necessary in a few applications for the closed state of the safety device to be capable of being locked in a releasable way, for instance when the safety device is to be prevented from being opened in an operating state of the machine; the lock is only released after a standstill of the machine, and the safety device can be opened.
In the case of safety switches with mechanical actuators, locking or blocking of that type is carried out by locking the mechanical actuator in the state introduced into a switch head of the safety switch, as known from DE 43 28 297 C1.
A safety switch is known from WO 98/43351 A1 with an actuator that has an inductor for a contact-free signal exchange with the safety switch, in particular with a reading head of the safety switch.